Static impedance and phase changing circuit



April 25, 1950 w. c. HALL 2,505,288

STATIC IMPEDANCE AND PHASE CHANGING CIRCUIT Filed Oct. 24, 1946 2Sheets-Sheet 2 I05 /07 E -/09- g /04 me /08 w. 6

I00 /02 95 L /o/ INVENTOR.

Patented Apr. 25, 1950 ENT OFFICE STATIC IMPEDANCE AND PHASE CHANGINGCIRCUIT Willard C. Hall, Los Angeles, Calif.

Application ctober'24, 1946, Serial No. 707,805 3 Claims. (01. 315-276)supplying discharge devices such as fluorescent lamps and the like.

In prior art, the improvement of power factor required the use ofcondensers in order to reduce the reactive volt amperes, which areinherent inthe operat on of discharge lam s and is 'an expensive methodfor low power transformer supply systems for discharge lamps requiringreactive regulation.

My invention does not employ the use of capacitive reactance toneutralize the inductive reactance', which is required for the effectiveregulation of current in discharge lamps but em' ploys a new an novelphase shifting circuit arrangement for starting the lamps and alsoregulating the current with a minimum reactance so that the line inputpower factor is 90 per cent or better. a

It is to be noted that if a reactor were used as a current equalizer, asshown in my Patent #2302313, that the lamps would actually be op eratingin parallel, thus, the load impedance reflected back to the line for twostandard 40 watt fluorescent lamps would be approximate y 150 ohms.However, in this invention whereby, the reactor transformer becomes ineffect a series current limiting impedance and the fact that the lampsare operated in series at an approximate impedance of 520 ohms, ascompared to 150 ohms in the former instance, it is readily understoodthat the reflected impedance of the series circuit arrangement willeffectively reduce the primary volt amneres, so that, the resultantpower factor approximating that of the lamps themselves may besecured.

One object of my invention is to provide a circuit combination employinga supply transformer and a reactor whereby the discharge lamps arestarted in parallel and operate in series, so that the transition fromthe starting cycle to the actualrunning voltage as supplied to the lampswill cause a phase shift in the reactor windings regulating the currentin the discharge lamps and also decreasing the reactive impedance.Another object of my invention is a unique circuit function which takesplace in the reactor circuit during the starting cycle and the runningor operating cycle so that the windings of the reactor during thestarting cycle. are circuit connected as an auto transformer, whichsupplies a voltage sufficiently high to initiate ionization in one ofthe lamps and when one of the lamps drops its voltage to the runningvoltage, the

alternate lamp is ionized and started and when 2' ning voltage thewindings of the series connected reactor are now functioning at aminimum phase relation and thus minimizing the reactive voltage inregulating the current supplying the discharge lamps.

A further object of my invention is to propor-. tion the secondarytransformer voltages and phase changing reactor voltages with respect tothe lamp drop voltages in such ratios so when the lamps are operating inseries they will require approximately one half the usual required voltamperes, thus reducing the supply current by the same equivalent givingan improved volt ampere ratio to the true power required for theoperation of the lamps.

A still further object of my invention is to provide a new and novelmeans of starting the lamps without the use of mechanical andthermostatic switches as employed in the conventional fluorescent lampcircuits, by taking advantage of the subtractive voltage secured by thephase shifting reactor circuit, it is possible to supply a sulficientlyhigh potential to alternate lamps and initiate the starting of the lampsand consequently subtract a considerable portion of this voltage fromthe lamps when the lamps are operating at their normal voltage drops.

Other objects and advantages of my invention will be apparent from astudy of the following specifications, read in connection with theacccmpanying drawings wherein:

Fig. 1 illustrates a series arrangement of a phase changing reactor autotransformer.

Fig. 2 illustrates an auto transformer circuit supplying the primaryinput.

Fig. 3 illustrates a filament heater circuit arrangement with a selfstarting lamp circuit.

Fig. 4 shows a diagrammatical drawing of the reactor windings.

Fig. 5 illustrates a circuit arrangement showing a glow discharge andcondenser lamp starting circuit.

Fig. 6 illustrates a circuit using a phase changing reactor directlyconnected to the line wire pply.

' Referring to Fig. 1, showing a circuit for oper-' ation of two 40 wattfluorescent lamps, resulting in an improved power factor withoutcapacitive reactance. l and 2 are two A. C. supply wires energizing ahigh impedance primary 3; 4 shows the core which is magnetized at a fluxdensity of approximately fifty thousand lines per square inch, byprimary 3 in order that the exciting cur rent may be kept relativelylow, as this is' an impcrtant factor in the reduction of the full loadprimary current. 5 and .6 show twoisolated windings supplying voltagesapproximately: 30

volts greater than the operating voltage of the lamps, this also reducesthe reflected lamp volt ampere relation to the input impedance, l4 showsa reactor auto transformer having parallel wound windings l and 8 whichserves the dual purpose of ballasting the lamps I1 and I8, as well as,supplying the required initiating voltage for alternately starting thelamps, it is seen that reactor 14 is series parallel connected throughwires l5, l6, [3, ll, l2, 9 and H) to the discharge lamps I! and I8,when switch 2! is closed, causing current to' flow through connectingwires 25 and 26 and through cathodes l9 and 20, also through wires 9, land l l, winding 7 of reactor [4 has a voltage impressed upon it,supplied from transformer winding 5, connected by wires l2 and it tolamp I1, the current heating the cathodes l9 and 20 will appear in wiresHi and H at the same time winding l acting as a primary with respect towinding 3 having a one to one ratio and at this instant the voltagesdeveloped through auto transformer action cause the E. M. F. in winding8 to add to that of winding 6, thereby, producing a voltage sufficientlyhigh in conductors 9, ill, I l and I connecting cathodes 2i and 22 oflamp 18, when switch 28 is opened to ionize lamp [8 and drop its voltageso that when switch 27 is opened, the reverse action now takes place,initiating ionization in lamp ll.

After lamps ll and it are operating at normal voltage drops itwill beseen that they are actually operating as series connected lamp loads,supplied from series connected supply windings 5' and 6 and the currentregulated through the now series connected windings l and 8 or reactorl4, connected to supply windings 5- and ii, and wire 9. At this point inthe circuit function of my invention,

is to be noted that, there is no current in conductor It, this is byreason of the fact that lamps H and 18 were initially started in seriesparallel and now since they are operating as series connected loads, thewindings 1 and 3 appear in the circuit connecting the two supplywindings 5 and 6 as series connected windings, thus the magnetic fluxesin the reactor core i i are in phase opposition. therefore, it isapparent that a minimum self inductance is introduced inregulatingreactor M.

Fig. 2 shows an alternate transformer arrangement for supplying power tolamps IT and i8 and reactor transformer I! as indicated in Fig. 1, thisarrangement comprises an auto transformer, which is more economical tomanufacture. 29 and 38 are line wire supply conductors connecting asection of windings 3| and 32 having an isolated winding 33, conductor28 is common with the line input circuit to lamp l8, conductor 33' conneots extended wind ng 32 to winding 35 of reactor transformer l lthrough conductor 49 to the opposite end of lamp It isolated winding 33connects one end of lamp I! through conductor 35 and the opposite endthrough conductor 31 and reactor winding 34 through conductor 39.

:3! which is part of one of the secondary windings Fig. 3 shows acircuit arrangement similar to Fig. 1, embodying filament heaterwindings, combined with a switchless lamp starting circuit.

4| and 42 are line wire supply means, connected to i primary 43 oftransformer 44, having a plurality of windings, namely three filamentsupply windings 49, 48 and 59, also two isolated lamp voltage supplywindings 45 and 46, cathode 68 is connected by conductors 64 and 62 tofilament supply winding 4?, also cathode 69 of lamp 6'! is connected byconductors 63 and 65 to filament winding 48, cathodes 10 and "H of lamps66 and 61 are series connected through conductors and 6| to filamentsupply winding 59. Lamps 66 and 61 are series connected through reactortransformer 5'! having windings 55 and 5'5 connected to mid point 58 offilament heater winding 59.

The discharge lamps 66 and 6! receive their supply voltage fromsecondary windings 45 and 46 having approximately 135 volts at full loadand connected through conductor 5! to mid point 49 of filament heaterwinding 41, and also through conductor 52 to mid point of filamentheater winding 48, the purpose of heating the cathodes 63, 69, 79 and Hof the lamps 66 and 61 is to decrease the cathodic voltage drop andcon-- sequently permit a corresponding decrease inthe operating voltamperes required for the operation of the lamps, thereby, decreasing theprimary input volt amperes with respect to power and improving the powerfactor.

Lamps and 6? receive their initial ionization potential without switchmeans by a new and. novel phase shifting circuit, comprising a'condenserl2 connected to one end of winding 45 through conductor 13 and to midtap 58 of filament winding 59 through conductor (4 which is in serieswith winding 56 of reactor transformer 51, whose opposite end isconnected through return wire 53 to winding 45, when winding 45has apotential of approximately 140 volts, condenser 12 displaces the phaserelation of reactor transformer windings 56 and 55 so as to inphasethese windings to a degree wherein a potential which is the vector sumof the voltages appearing in windings 46 and 55, which are impressedacross lamp 61, the vector sum of these voltages is sufiii fieientlyhigh to initiate ionization in lamp 61.

When lamp 6'! drops its voltage to its normal running potential, winding55 of reactor trans former 51 will have a voltage impressed upon it byaction of the voltage now appearing acrosswinding 55,'which is additivevecto-rially to wind ing 45, the sum of these voltages will now initiateionization in lamp 66, and as lamp 66 drops its voltage to the runningvoltage of this lamp, the induced voltages in windings 55 and 55 of theregulating reactor 5'! have their maximum phase displacement and nocurrent will flow through conductor 58, thus lamps 65 and 6! areactually operating in series, the current being regulated through theefiective impedance drop of winding 55 and 56.

Fig. 4 shows a diagrammatical drawing of one form of a reactortransformer. 18 shows a shell type iron core having outer limbs ll andI9. .15 and 1B show two insulated wire conductors, which have a. commonwinding point and are wound parallel with respect to each other, thisis. done for the purpose of reducing the self inductance of the windingsto a minimum.- .80 represents the space between the parallel woundconductors, Which should be uniform throughout the whole winding of thecoil.

Fig. 5 shows an arrangement similar to Fig. 1, but having a novel lampstarting circuit arranged so that no currentor voltage appears in theswitch circuit after the lamps have been. started. 8| shows .aihighimpedance primary winding, .82 and 83 are isolated windings connected bywires 88, 86,

81 and 89 to lamp loads 90 and 9| through a com-'- mon conductor 92, toreactor transformer windings 84 and 85. It is to be noted, that, commonconductor 92 connects condenser 93 and switch means 94, which preferablyis a negative glow discharge device having an extinction voltage abovethe operating voltage of the parallel connected lamp 9I, so that,ionization will not take place while lamp 9| is operating at its normalvoltage drop, so that therefore, no voltage will appear wherein, the useof a line transformer may be eliminated for the operation of standard118 volt line wire supply means connecting one end of reactortransformer 91 to winding 98, and also to one end of cathode I 04 oflamp I08, switch means I03, which may be of the thermostatic or gasfilled type, connects cathodes I04 and I05 through conductor I02 to theisolation'winding 99 of reactor transformer 97, this winding is alsoconnected to one end of cathodes I06 and I01, the

opposite end of these cathodes have their return circuit throughconductor I00 and winding 98 to line wire 96 of the reactor 97. It isreadily seen, that in this low voltage circuit arrangement, that lampsI08 and I09 will operate in series when starter switch I03 is opened,the current in the lamps is effectively ballasted through windings 98and 99, as well as, the parallel cathodes I06 and I 01, which in thisparticular circuit arrangement will have a normal cathodic voltage drop.

When switch means I03 is closed, the filaments of lamps I08 and I09 areraised to their normal emission, the reactor 9! acts as a currentregulating means to limit the starting current through the filaments ofthe lamps as well as providing an inductive discharge or kick, whenswitch I03 is opened, thereby, ionizing the gas or vapour in lamps I08and I09, when the lamp voltage drops It is preferable to the normaloperating voltages, the reactor 91 will have a very low phasedisplacement with respect to voltage and current supplying the lampcircuit in as much as the inductance of the reactor 91 is of a minimumvalue due to the phase changing windings 98 and 99. Oscillographicanalysis shows that the phase relationship between windings 98 and 99apparently changes through each half cycle of lamp operation, whichindicates a variable impedance cycle which effectively assists in theballasting of lamp load.

I claim:

1. In a series-parallel circuit for starting and operating electricaldischarge lamps; the circuit comprising transformer means having aprimary for connection to a source of suitableelectrical current and asplit secondary having outer coilend terminals and inner coil-endterminals, an electrical discharge lamp bank having aplurality of lampswherein each lamp has an electrode at each end thereof, a central tapconnecting proximal electrodes of the lamps, an electrical ballast unithaving a pair of series connected coils with a central tap and which areout-of-phase with respect to each other substantially electricaldegrees, a conductor connecting the two mentioned central taps, thedistal ends of the unit having terminals which are series connected tothe innercoil end terminals, respectively, of the secondary of thetransformer, and each lamp of the lamp bank having a shunt-switch meansacross its electrodes which can be closed to heat the lamp and thenopened for current discharge between the electrodes of the lamp.

2. In a starting and operating electrical circuit for electricaldischarge lamps and the like; the circuit comprising a transformer meanshaving a suitable primary for receiving current from a suitable source,the transformer means having a plurality of secondary coils forsupplying current to a plurality of lamps and a ballast unit in serieswith the said secondary coils, a plurality of lamps of electricaldischarge type wherein each lamp is provided with'an electrode at eachend thereof, conductor means connecting the secondary output of thetransformer with one electrode of each lamp, the other electrode of eachlamp having a common conductor connected thereto, the ballast unithaving two coil means which are wound 180 electrical degrees apart andwhich have a common connection that is electrically connected to theaforesaid common conductor, and a switch means for each lamp andshunting the electrodes of each lamp so as to cause current to flow inorder to heat its respective lamp when the switch thereof is closed, butto cause space discharge in its respective lamp when it is opened.

3. In a circuit means for starting and operating electrical dischargelamps and the like, the circuit consisting of a transformer having aprimary for connection with a suitable supply of electrical current anda secondary having a plurality of coils with a ballasting unit in seriestherewith and connected thereto at a central point thereof, the unitconsisting of a plurality of series connected coils wound in oppositephase relationship with a central tap, a pair of discharge lamps with aheating means at each end of each lamp, one heating means of each lamphaving an end thereof connected to the said secondary and the otherheating means of each lamp having a common electrical connection andalso connected to the aforementioned central tap of the ballasting unit,the other terminals of each set of heating means of each lamp havingconnection with a switch means that is adapted to connect the secondaryin series with all the heating means of its respective lamp when theswitch is closed, but when opened, to cause discharge of current betweenthe heating means of its respective lamp.

WILLARD C. HALL.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS

